Hey guys, I have a bone stock 2004.5 duramax. Sometimes it has a really rough idle. I can only notice it when its in gear and i am at a stop. I can hear the engine "laboring" at one spot and it lunges forward at that exact spot. All i have done to it is exhaust and i dont know what woulkd make it run like this. when im driving along in overdrive and i come to a complete stop slowly, i can hear the engine running rough as the transmission downshifts but you cant notice it untill you have your foot on the brake trying to hold the truck there. Any ideas, thank you